It should be recalled that the leading edge corresponds to the front part of an aerodynamic profile which meets the air-flow and which divides the flow of air into an intrados or lower-surface airflow and an extrados or upper-surface airflow. The trailing edge corresponds to the rear part of an aerodynamic profile where the intrados and extrados flows re-unite.
The turbine engine blades, and in particular fan blades, are subjected to high levels of mechanical stress, associated in particular with the speed of rotation, and must meet strict weight and overall size conditions. Consequently blades made of composite materials are used which are lighter.
Fan blades fitted to turbine engines are known which are made of composite materials, and in which a metal structural reinforcement extends over the entire height on either side of their leading edge as stated in document EP1908919. Such a reinforcement protects the composite blading during impacts by foreign bodies on the fan, such as, for example, a bird, hail or even stones.
In particular the metal structural reinforcement protects the leading edge of the composite fan by preventing the possibility of de-lamination, fibre breakage or damage due to fibre/matrix bonding failure.
Conventionally a turbine engine blade includes an aerodynamic surface which extends, in a first direction, between a leading edge and a trailing edge and, in a second direction which is substantially perpendicular to the first direction, between the root and the tip of the blade. The metal structural reinforcement follows the shape of the leading edge of the aerodynamic surface of the blade and extends in a first direction on either side of the leading edge of the aerodynamic surface of the blade to follow the profile of the intrados and of the extrados of the blade, and in the second direction between the root and the tip of the blade.
In a known manner the metal structural reinforcement is a metal part made of titanium manufactured entirely by milling from a block of material.
However, the metal reinforcement of a leading edge of a blade is a complex part to make, requiring numerous re-work operations and complex tooling which involves high manufacturing costs.